Call metering in telephone systems



N. E. NILSSON CALL METERING IN TELEPHONE SYSTEMS Filed June 18, 1930 Patented lice. 8, 1331 sraras L. M. EBICSSON, OF STOCKHOLM,SWEDEN, REGISTERED COMPANY CALL METERING n TnLEPHoNEsYsrmus Application filed June 18, 1930, Serial no. esa oa nd in Sweden nine 21;[1929.ff 1 The present invention relates to a call me over certain junction lines-by way of exampie trunk lines connecting difierent telephone exchangesare sub ect-ed to a special charge, which is reglstered on the call meter through the intermedinm of impulse senders, which are adapted to actuate the call meter in accordance with the tarif in force for the connection in question. Further the invention relates to certain arrangements for transmitting the call meter impulses over they talking connection and for actuating the im pulse senders connected to the talking connection, so that said impulse sender'smay be successively started to send out current impulses to thecall meter. v

The invention will be more closely described with reference to the accompanying drawing, which shows two impulse senders with appertaining impulse repeating devices, connected to a talkin connection in an autoll'lRtlQtBlCPllOIlG plant. Each impulse sender with appertaining impulse repeating device forms an impulse sender set, which prefer ably is common to a plurality of junction lines, and which, when the junctionline is used, is automatically connected to the junction line. If desired, each unction line may be providenwith such an'impulsesender set.

lhe drawing shows only those parts of the alking connection which have anythingto do with the impulse metering. I In the shown example the call ineter'impulsesare transmitted to thecall meter SR over the third wires 0 c 0 of the talking connection.

Said wires include relays R R R Ri, R

R which are energizedduring the call, and oi which the relays R and B and R are used. for transmitting the call meter impulses. In the shown example it is assumed that the connection is carried over two junction lines which connect exchanges belonging todifferent' tarifi zones, and that aspecial' charge is to bere'gisteredfor each one'of these junction lines; Twoimpulse senders 1S andIS' with appertaining: impulse repeatmg devices IE and IE are therefore connected to; the- 1 talking connection. It is} assumed in this case that the callsa're tobe'charged for according to a combined zone and time .tarifi, the arrangement being such, that the impulse sender sets are brought into operation periodically at even intervals of time, bywa of,

example every three minutes: The call inetering operation is started by'a-n interrupter PS,'disposed, by Way of example, at'the last selector of the talking connection, which interrupter starts the impulse sender TS by means of a currentimpulsef Said-impulse sender then sends out a number of call'met er impulses corresponding "to the appertaining junction line; whichiimpulses a e transmitted and repeated by the impulse repeating device 1R of'the other impulse sender set. Theinr pulse sender" TSi then starts the impulse sender TS which in turn sends out-a number of call 'lneter impulses corresponding to the appertaining junction line, "which call meter impulses aretransmitted'to thecall meter.

The impulse sender sctsshallthus be able torepeat the current impulses sent out from another impulse sender? set a and "shall also be able to startanother impulse sender set such a way,"that foreach time interval'all the impulse sender s'etsconnected to the talk-' ing connection aresuccessively, brought into operation and sen'd' fou't their. series of im' pulses, which, will thus actuate the call meter in sucha wayft-hat thesum of thecliarges for the different junction lines is registered; As

the transmission of impulses as Well-as the starting of the impulse senders must be ef fected overthesame circuits the arrangement according tothe invention is such, that the call meter and the impulse sender are'a'ctuated by current impulses-of different jkinds,

preferably current impulses ofdiflerent du-' ration are utilized, the impulse sender being started by means of current impulses of longer duration than the call meter impulses.

If desired, the call meter may be adapted to be actuated by both kinds of impulses, in whichcase the last call meter impulse sent out by one impulse sender at the same time can start the next impulse sender. The drawing shows an embodiment of this kind.

In the embodiment shown on the drawing theimpulse-sender aswell' as the appertainingrepeating device is formed as an electromagnetic stepping mechanism provided with rotating cams or the like, which control the sending out ofimpulses. The impulse sender is driven by means of anelectromagnet SM, which through the intermedium of a stepping mechanism, which is not shown on the drawing, can impart a step-wise rotating motion to a shaft. A control disc KS and also animpulse disc SS are attached to this shaft. The first mentioned disc'isadapt- ,edto actuate a contact spring K which con nects the drivingmagnet SM into an impulse circuitas soonas the impulse sender is. driven out of its normal position, and whichiisactuated by the-discKS, so that the impulse sender, after-it; has been startedyis turned a complete revolution. During this motion the impulse disc SS actuates a contact springK by means of which impulses for actuating the callmeter and for starting the next impulse-sender are sent out.

The impulserepeating device TB is intended to repeat the call meter impulses and to serve as an intermedium for starting the appertaining impulse sender. For this purpose it is designed as a time relay in such a way,.that theimpulse, sender is started only when the impulse repeating device is actuatedyby a current impulse of shorter durationtha-n theimetergimpulses. The impulse repeatin device is provided with a driving magnet 3M,which by means of an'armature SA and.a;driving pawl DH isrotata-bly connected to the former. and can impart a stepwise rotating motion to a toothed wheel SH; Thedrivingpawl DH is-by means of a spring normally held in ,an inoperative position, but is. adapted to be brought into engagement withthe teeth ofthe wheel'Sl-T by means of a magnetuRM and an appertaining armature RA. The repetition-of the. impulses is brought. about by closing the contact springs K K of whichithe-former is fastenedto the armature RAv and the latter adapted to co-operate with a caniRS, which is rigidly attached ,to the same shaft as the wheel SH. The magnets RM and AM-are adapted to be connected into. circuit simultaneously over normallyclosedcontacts 1 and 2 respectively of; therelays R andR respectively. The magnetrAM is ,thenconnectedinto a circuit co-m prisinganinterrupter PS, .the wheel SH being thus made to rotate. The magnet RM on the other hand remains permanently energized. The contact K Ii -remains closed, however, only until the wheel SH has been moved forward a few steps, as the cam BS is then disengaged from the spring K so that said contact is opened. If the impulse starting the impulse repeating device is of longer duration the magnet AM then continues to move the wheelSl-l forwards until a pin S, disposed on said wheel, engages and closes contacts 3 and 4 respectively, when the magnet SM of the impulse sender is connected into an impulse circuit including an interrupter PS, The magnet SM then attracts its armature and thereafter receives current over the contact spring K, until the shaft of the impulse sender has rotated one revolution, when the contact spring K interrupts the circuit for the magnet SM. Meanwhile the current impulse, which started the impulse repeating device, has ceased through interruption of the contacts 1 and 2 respec tively. l/Vhen on account of this the magnets RM and AH are deenergized, the

wheel SH and the cam RS are through spring action restored to their'normal position shown on the drawing.

a The switching operation in call metering is as follows. lVhen the talking connection is established the interrupter TS will periodically short-circuit the relay R over the contact 5. This short-circuit is of such a duration, that the impulse sender 1S is started thereby. When the relay E on account of the short-circuitdrops its armature, the mag- .nets RM and AM of the impulse repeating device are again connected into circuit over the contact 1. The relay R is then initially short-circuited over the contact springs K IQ. Said short-circuit is, however, of such a short duratiomtha-t it cannot start the impulse sender 1S On the other hand the impulse repeating device IE is actuated by closing the contact 2; The relay R is then short-circuited over the contact springs K K. of said impulse repeating device. When on this account the relay R drops its armature the call meter SR receives a current impulse over the contact 6 whereby the first charge. is registered. Meanwhile the impulse repeatingdevice TR has continued to operate. As soon as the short-circuit of the relay R at the contactK K is interrupted the impulse repeating device IE is restored to its normal position. which restoration takes place before the impulse sender 1S is started. lVhen the pin S on the toothed wheel of the impulse repeating device 1R closes the contact 3'th-e impulse sender 1S is started inthe above described manner. The contact spring K then short-circuit the relay R a number of times corresponding to the number ofteeth on the impulse disc SS.

The number of saidteeth corresponds tothe tion. In the shown example the impulse sender is provided with 3 teeth, the last of which is so wide, that it brings about a shortcircuit of the relay R of long duration and thus starts the impulse sender IS The first two teeth, on the other hand, generate only impulses of short duration, which in the manner described above are repeated by the impulse repeating device IE and are registered by the call meter SE. The third tooth at first brings about a short-circuit of the relay R of short duration over the contact springs K K and then starts the impulse sender 15 which then in turn sends out a number of impulses corresponding to the junction line in question, in the shown eX- ample three impulses, which short-circuit the relay R and are thereby registered by the call meter.

From the above it is clear, that the impulse repeating devices are arranged in such a way, that they at the same time are able to transform the one kind of current impulses to the other kind of current impulses, that means, a current impulse of long duration to a current impulse of short duration. Said arrangement is required to prevent that a current impulse of long duration, at the same time as it is transmitted to the call meter, shell be able simultaneously to start all the impulse senders connected to the talking connection. The impulse of long duration sent out from the interrupter TS is thus transmitted to the call meter SR first after it has been transformed to an impulse of short duration by means of the cam RS of the impulse repeating device. which impulse 1R of short duration is then repeated by the repeating device IR but does not start the impulse sender IS The starting of an impulse sender can of course also be brought about by means of a special current impulse, which is sent out i, m another impulse sender first after the call meter impulses have been sent out, and which should therefore not be registered by the call meter. Said starting impulse can also. if desired, be of an entirely different k' id than the call meter impulses, by way of rmple an alternating current impulse. in which case both kinds of current impulses may be transmitted over the same circuits,ii arrangements are only made to prevent the call meter from being actuated by the current impulse starting the impulse sender.

I claim:

1. In a switchin arran ement for call metering in telephone plants a number of junction lines connecting different tariff zones and provided with impulse senders for sending out to a call meter a number of current impulses corresponding to the charge for the appertaining junction line, and

' 1 means to actuate said call meter and the impulse senders over the same circuits by means of current impulses of different kinds.

2. In a switching arrangement according to claim'rl, means to send'out impulses of different kindsin such a way, that said impulse sender after impulses, automaticallystarts another impulse sender connectcd to the talking-connection. 3

3. Ina switching arrangement for call metering in telephone plants a ,numberof junction lines connecting different tariff sending out the call meter zones and provided with impulsesenders for V sendingoutto a call meter 'a number of c-ur- H rent impulses corresponding'to the charge actuate said call meter and the impulse senders by means of current impulses of two kinds, the call meter being adapted to be actuated by both kinds of impulses while the impulse sender is adapted to vbe started by only one kind of impulses.

4. In a switching arrangement for call metering in telephone plants anumber of unction lines c'onnectmg dillerent tarifl zones and provided with impulse senders for sending out to a call meter a number of current impulses corresponding to the charge for the appertaining junction line, means to, actuate said call meter and the impulse sendlcinds, the call meter being adapted to be actuated by both kinds of impulses while the impulse sender is adapted to be started by only one kind of impulses, and means to so, for the a ertalnin unction line means to PP 7 ers by means of current impulses of two ransform the impulses intended for startimpulse sender isadapted to bev started by.

only one kind of impulses and means to transform the impulses intended for start ing of the impulse sender to a Callmeterimpulse the former impulsesbeing of a longer duration than the call meterim'pulses.

(3. In a switching arrangement, for call metering in telephone plants, a number of junction lines connecting different tariff zones and provided with impulse senders for sending out to a callmeter a number of current impulses corresponding. to the charge for the appertaining junction line, means to actuate said call meter and the impulse senders by means of current impulses of two kinds, the call meter being. adapted to be Y actuated by both kinds of impulses While the impulse sender is adapted to be started by only one kind of impulses, and means to transform the impulses intended for starting of the impulse sender to a call meter impulse the former impulses being 'of a longer duration than the call meter impulses electromagnetic means adapted to be started by impulses to be transmitted and to repeat said impulses in the form of'impulses of short duration independently of the duration of the. starting impulse.

In testimony whereof I affix my signature NILS EMIL NILSSON. 

